Periodic TableAll elementsXenon
No. 054
Xe
131.29 u
Element · Noble Gas

Xenon

Xenon (氙, symbol Xe) is chemical element number 54, a Noble Gas in period 5, group 18 of the periodic table, with a standard atomic weight of about 131.29. Heavy, colorless noble gas. Used in flash lamps and ion engines for spacecraft.

Period 5Group 18[Kr] 4d¹⁰ 5s² 5p⁶

Properties

Atomic number54
SymbolXe
Atomic mass131.29 u
CategoryNoble Gas
Period5
Group18
Electron configuration[Kr] 4d¹⁰ 5s² 5p⁶
Electronegativity2.6
Covalent radius140 pm
Density0.005887 g/cm³
Melting point161.4 K
Boiling point165.03 K
DiscoveryRamsay & Travers, 1898

Overview

Heavy, colorless noble gas. Used in flash lamps and ion engines for spacecraft. Xenon (Xe) is a Noble Gas with atomic number 54, located in period 5, group 18. As a noble gas it has a full outer shell, is extremely unreactive, and exists as a monatomic gas at room temperature.

It has the configuration [Kr] 4d¹⁰ 5s² 5p⁶ and an electronegativity near 2.6; its 8 outer-shell electrons drive its bonding. Under standard conditions it exists as a gas (a very low melting point); it melts near 161.4 K (-111.7 °C), boils near 165.03 K (-108.1 °C), has a density around 0.005887 g/cm³.

It is widely used in Industrial Gas and Medical / Pharma. It was first described by Ramsay & Travers in 1898. The periodic trends guide explains the underlying patterns.

Electron shells

Xe54

Electrons per shell: 2 · 8 · 18 · 18 · 8

Main uses

Hazard

LowNo special hazard flags.

Compounds containing Xenon

No compounds in this knowledge base contain Xenon yet.

Data sources

Atomic mass uses IUPAC (CIAAW) standard atomic weights; the covalent radius is from Cordero et al. (2008). Verify on the RSC Periodic Table, PubChem and Wikipedia. Educational reference only.